arpadveress 
“Normal operation” means the situation when installations are used within their design parameters.
Is the average user aware of what is normal operation? Mainly we are focusod on functionality and less on normal operation. Specialy in potential hazardous environment where it says 1) Ex 2) functionality.
My alltime best example an Ex fluorescent light fitting certified with tube A – it works pretty well with tube B, but not Ex.
Keep up good work!
Arpad
